Leaded gasoline containing phosphorus



United States Patent 2,984,552 LEADED GASOLINE CONTAINER} PHOSPHORUSEverett N. Case, Homewood, 11L, assignor to Sinclair Refining Company,New York, N.Y., a corporation of Maine No Drawing. Filed Nov. 19, 1957,Ser. No. 697,318 2 Claims. (Cl. 44-69) My invention relates to improvedgasoline which is of high octane number and which contains tetraethyllead as an anti-knocking agent.

By and large, modern gasolines for use in spark-ignited internalcombustion engines have an octane number of at least 85 RON, that is, asdetermined by the Research Method, and they contain tetraethyl lead,generally within the range from 0.5 to 3.0 cc. per gallon, or even asmuch as approximately 4.5 cc. per gallon, as a knock-suppressing agent.Tetraethyl lead is the most widely used antiknock agent, and is veryeffective for this purpose, but it sutfers from the defect that itcauses lead-containing deposits in the cylinders. These deposits have atendency to cause preignition; that is, the deposits are hot and causethe mixture in the cylinder to burn before combustion is initiated atthe proper time by the spark plug. Preignition can be controlled, as theart is aware, by the addition of phosphorus additives to leadedgasoline. However, the phosphorus additive must be properly chosen orotherwise when the engine is put into service and operated, the octanerequirement increase .encountered as the engine cylinders build updeposits will be greater than that which takes place when no phosphorusadditive is used.

In accordance with my invention, yellow phosphorus (sometimes known aswhite phosphorus or alpha-white phosphorus) is incorporated into leadedgasoline with the result that preignition is suppressed and the octanerequirement increase as the engine is used is less than that encounteredwith the base fuel, that is, the gasoline not containing any phosphorusadditive. The yellow phosphorus is incorporated into the gasolinegenerally in the amount of from 0.1 to 2 theory, and preferably in theamount of from 0.2 to 0.6 theory, 1.0 theory meaning that for each threegram atoms of lead present in the tetraethyl lead there are present twogram atoms of yellow phosphorus. One theory is based upon the premisethat the phosphorus and the lead in the tetraethyl lead react in thecombustion zone to form lead orthophosphate, Pb (PO Stated somewhatdifferently, for each three gram moles of tetraethyl lead present in thegasoline, there is also generally present from 0.2 to 4 gram atoms ofyellow phosphorus and preferably from 0.4 to 1.2 gram atoms of yellowphosphorus.

Example ASTM distillation of the gasoline was as follows:

F. Initial boiling point 115 percent 210 50 percent 324 90 percent 357End poin 421 fiice Into a portion of the base gasoline there wasdissolved 0.3 theory of yellow phosphorus, this amount being 0.0936 gramof yellow phosphorus per gallon of base gasoline. When the base gasolineand the base gasoline containing the yellow phosphorus were subjected tocomparative tests in a spark-ignited single cylinder combustion engine,it was found that the gasoline containing the yellow phosphorus showed aping count per hour of 157 and that the base gasoline showed a pingcount per hour of 333.

A second sample of base fuel was obtained, this particular sample beingcomposed of a mixture of alkylate, heavy reformate from straight runnaphtha, light fluid cracked gasoline and butane. This particulargasoline contained 3 cc. per gallon of tetraethyl lead together with theusual scavengers, had an API gravity of 53.6, an octane number by theResearch Method of 101.4 and an octane number by the Motor Method of91.4. The ASTM boiling range of the second base gasoline was as follows:

F. Initial boiling point 5 percent 118 50 percent 264 90 percent 319 Endpoint 381 Into a portion of the second base gasoline there was dissolvedyellow phosphorus in the amount of 0.3 theory. The second base gasolineand a portion thereof containing the yellow phosphorus were then testedin a 1957 model automobile engine for octane requirement increase, withthe results shown in the table below:

Engine octane requirement 1. Gasoline containing from 0.5 to 4.5 cc. pergallon of tetraethyl lead and also containing yellow phosphorus in theamount of from 0.1 to 2 theory.

2. Gasoline containing from 0.5 to 4.5 cc. per gallon of tetraethyl leadand also containing yellow phosphorus in the amount of 0.2 to 0.6theory.

References Cited in the file of this patent UNITED STATES PATENTS1,913,970 Albers June 13, 1933 2,405,560 Campbell Aug. 13, 19462,563,101 Colwell et a1 Aug. 7, 1951 2,794,717 Gilbert June 4, 19572,797,153 Bereslavsky June 25, 1957 FOREIGN PATENTS 709,653 GreatBritain June 2, 1954 1,094,828 France May 24, 1955 1,123,123 FranceSept. 18, 1956 OTHER REFERENCES Petroleum Refining With Chemicals," byKalichevsky et aL, Elsevier Publishing Co., 1956, p. 491.

1. GASOLINE CONTAINING FROM 0.5 TO 4.5 CC. PER GALLON OF TETRAETHYL LEADAND ALSO CONTAINING YELLOW PHOSPHORUS IN THE AMOUNT OF FROM 0.1 TO 2THEORY.